Question

A boy agrees to work at the rate of one rupee on the first day, two rupees on the second day, and four rupees on third day and so on. How much will the boy get if he started working on the 1st of february and finishes on the 20th of february?

Answer 1

Answer:

hey mate there's your answer

On working on first day the boy gets Rs.1

On second day he gets Rs.2

On third day he gets Rs.4

This series can be written as,

1+2+4+8+................upto 20 terms.

1+2^1+2^2+2^3+...........,........upto 20 terms.

It is in Geometric progression.

with first term t1=1 and second term t2=2

and common ratio r=t2/t1=2/1=2

so common ratio is 2.

we know that sum of n terms in GP is,

Sn=t1(r^n-1)/(r-1)

S20= 1(2^20-1)/(2-1)

=2^20/1

=2^20-1

=1048576-1

=1048575

so the boy gets Rs. 1048575 on working for 20 days.

hope it helps you......

Thank you!!!